How to Use the Eleven v3 API: text to speech integration guide (2026)
Learn how to call the Eleven v3 API on NamiFusion: parameters, pricing (from ≈$0.010) and runnable copy-paste code — try it in the playground first.
Eleven v3 is a text to speech model by ElevenLabs: The most expressive model. Supports 70+ languages. Requires more prompt engineering than our previous models. On NamiFusion you can try it in the playground (exact quote shown before you submit), then call it through one unified REST API — a typical run costs about $0.010.
TL;DR
· Task type: text to speech, provided by ElevenLabs
· Pricing: about $0.010 per typical run ($1 = 100 credits), pay-as-you-go
· Getting started: playground (exact quote before submit) → create an API key → one POST request
· Tunable parameters: 4 (see the table below)
· No platform watermark; commercial use allowed (per the Terms of Service)
What can you build with Eleven v3?
Voiceovers and narration: generate multi-language voices for short videos, courses and ads.
Audio content production: turn articles, news and fiction into publishable audio at scale.
Product voice interfaces: consistent branded voices for apps and devices.
How do you call this API?
1. Sign up on NamiFusion and create a key on the API Keys page (free credits on signup).
2. Submit a task with the cURL example below, passing your key as a Bearer token.
3. Poll the task status with the returned task_uuid and read the output URLs when completed.
# 1) Submit — returns { "task_uuid": "..." }
curl -X POST "https://www.namifusion.com/api/v1/marketplace/run/eleven_v3" \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"input": {
"voice_id": "JBFqnCBsd6RMkjVDRZzb",
"language_code": "en",
"similarity_boost": 0.8,
"stability": 0.55
}
}'
# 2) Poll until status is "completed", then read the output URLs
curl "https://www.namifusion.com/api/v1/marketplace/run/tasks/TASK_UUID" \
-H "Authorization: Bearer YOUR_API_KEY"What parameters does it take?
voice_id (声音id): required
language_code (ISO 639-1语言code): optional
similarity_boost (Similarity Boost): optional, default 0.75
stability (Stability): optional, default 0.5
How much does it cost?
Pay-per-use in credits. A typical run costs about $0.010 ($1 = 100 credits); the exact price varies with parameters like resolution or duration, and the playground shows the exact quote before you submit.
Eleven v3
A high-naturalness text-to-speech model for fast, expressive voice generation with no cold starts.
Eleven V3 is ElevenLabs’ hosted text-to-speech model designed to turn written text into clear, lifelike, and expressive speech. It combines strong voice quality, low operational friction, no cold starts, and affordable usage-based pricing, making it a practical choice for production voice workflows.
🚀 Key Features
- High naturalness: Produces human-like intonation, pacing, and articulation for polished audio output.
- Expressive speech synthesis: Delivers clear pronunciation with lifelike emotional tone, suitable for narration and branded content.
- Controllable voice behavior: Fine-tune output with similarity and stability to balance realism, consistency, and speaker likeness.
- Speaker Boost support: Improves English text normalization, especially for numbers, times, and measurements.
- Multi-language capability: Supports multiple languages with strong overall intelligibility, while performing best in English.
- No cold starts: Hosted inference is ready to use for responsive, production-friendly generation.
🛠️ Technical Specifications
| Item | Details |
|---|---|
| Model architecture | Deep-learning text-to-speech（TTS）model |
| Model name | Eleven V3 |
| Input | Text string, voice_id string |
| Output | Audio file URL |
| Output format | MP3 |
| Maximum input length | 10,000 characters |
| Billing unit | 1 character = 1 token; charged per character |
| Voice options | Built-in voice library including Alice, George, Lily, Daniel, and more |
| Adjustable controls | similarity（0.0–1.0）, stability（0.0–1.0）, use_speaker_boost（boolean） |
| Pause control | Use <#x#> between words to control pause length（0.01–99.99s） |
| Language support | Multi-language text-to-speech; best performance in English |
| Latency | No fixed latency published; hosted deployment is positioned for no-cold-start responsiveness |
| Best practice | Split long passages into smaller segments for more stable rhythm and delivery |
Sample prompts
Note: This is a text-to-speech model, so it does not use Prompt / Negative Prompt in the image-generation sense. The examples below are sample input texts.
Welcome to our advanced text-to-speech system! Experience high-quality voice synthesis with natural pronunciation and clear articulation.The meeting will begin at 9:30 AM <#0.5#> and will cover sales performance, regional forecasts, and next quarter planning.Welcome to our product overview. Today, we’ll introduce a faster and more natural voice experience for digital content.
💰 Pricing
| Item | Price |
|---|---|
| Base price | $0.1 / 1,000 characters |
FAQ
Can I try it for free first?+
Signup gives you free credits, but they currently apply only to selected in-app face-swap features — this model is pay-as-you-go. The playground still lets you try it without code, with the exact quote shown before you submit.
Can I use the output commercially? Is there a watermark?+
Yes, outputs are yours to use commercially, and NamiFusion adds no platform watermark — subject to the Terms of Service and applicable law.
What is the content policy?+
NamiFusion is an unfiltered engine: no arbitrary restrictions and NSFW-friendly, but illegal content and non-consensual use of real people are prohibited — see the Terms of Service.
How long does a Eleven v3 task take?+
It depends on parameters — images usually take seconds, videos tens of seconds to minutes. The API returns a task_uuid for polling.
What are the resolution and duration limits?+
See the parameter table above — each model lists its available resolution and duration options there and in the playground.